Imaging Flexible DNA 'Building Blocks' in 3-D

Over the past decade, researchers have been working to create nanoscale materials and devices using DNA as construction materials through a process called “DNA origami.”

Now, for the first time, a team of researchers from Lawrence Berkeley National Laboratory (Berkeley Lab) and Ohio State University have generated 3-D images from 129 individual molecules of flexible DNA origami particles. Their work provides the first experimental verification of the theoretical model of DNA origami.

The research team focused on DNA structures modeled after a basic mechanism called a “Bennett linkage,” which is a 3-D structure consisting of a chain of four rods connected by hinges. This creates a skewed quadrilateral shape in which the hinges are not parallel or in-line. Using Bennett linkages as building blocks, it’s possible to create expandable, useful structures, like supports for tents that can be rapidly assembled.

The researchers relied on a technique developed at the Molecular Foundry to image the individual molecules that make up these structures. The method, called individual-particle electron tomography (IPET), takes pictures of a target molecule from multiple viewing angles, and then combines these pictures to create one 3-D, whole-molecule rendering, similar to how a medical computed tomography (CT) scan works.

Researchers captured 129 3-D images, with a resolution of 6 to 14 nanometers, that enabled them to tease out information about the dynamics and flexibility of DNA origami structures.